package com.linglan.common.handler;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;

/**
 * @author panjinxin
 * @date 2023-08-13
 */
@Slf4j
@Component
@Lazy(false)
public class SpringContextHolder implements ApplicationContextAware, DisposableBean {

  private static ApplicationContext applicationContext = null;

  /**
   * 取得存储在静态变量中的ApplicationContext.
   */
  public static ApplicationContext getApplicationContext() {
    return applicationContext;
  }

  /**
   * 实现ApplicationContextAware接口, 注入Context到静态变量中.
   */
  @Override
  public void setApplicationContext(ApplicationContext applicationContext) {
    SpringContextHolder.applicationContext = applicationContext;
  }

  /**
   * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
   */
  @SuppressWarnings("unchecked")
  public static <T> T getBean(String name) {
    return (T) applicationContext.getBean(name);
  }

  /**
   * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
   */
  public static <T> T getBean(Class<T> requiredType) {
    return applicationContext.getBean(requiredType);
  }

  /**
   * 清除SpringContextHolder中的ApplicationContext为Null.
   */
  public static void clearHolder() {
    if (log.isDebugEnabled()) {
      log.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext);
    }
    applicationContext = null;
  }

  /**
   * 发布事件
   *
   * @param event
   */
  public static void publishEvent(ApplicationEvent event) {
    if (applicationContext == null) {
      return;
    }
    applicationContext.publishEvent(event);
  }

  /**
   * 实现DisposableBean接口, 在Context关闭时清理静态变量.
   */
  @Override
  public void destroy() {
    SpringContextHolder.clearHolder();
  }

}
